Reland of 'Move content/browser/power_save_blocker to //device/power_save_blocker'

content/public/browser/power_save_blocker.h

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
-#define CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_
-
-#include <memory>
-#include <string>
-
-#include "base/memory/ref_counted.h"
-#include "base/sequenced_task_runner.h"
-#include "base/single_thread_task_runner.h"
-#include "content/common/content_export.h"
-
-namespace content {
-
-// A RAII-style class to block the system from entering low-power (sleep) mode.
-// This class is thread-safe; it may be constructed and deleted on any thread.
-class CONTENT_EXPORT PowerSaveBlocker {
- public:
-  enum PowerSaveBlockerType {
-    // Prevent the application from being suspended. On some platforms, apps may
-    // be suspended when they are not visible to the user. This type of block
-    // requests that the app continue to run in that case, and on all platforms
-    // prevents the system from sleeping.
-    // Example use cases: downloading a file, playing audio.
-    kPowerSaveBlockPreventAppSuspension,
-
-    // Prevent the display from going to sleep. This also has the side effect of
-    // preventing the system from sleeping, but does not necessarily prevent the
-    // app from being suspended on some platforms if the user hides it.
-    // Example use case: playing video.
-    kPowerSaveBlockPreventDisplaySleep,
-  };
-
-  // Reasons why power-saving features may be blocked.
-  enum Reason {
-    // Audio is being played.
-    kReasonAudioPlayback,
-    // Video is being played.
-    kReasonVideoPlayback,
-    // Power-saving is blocked for some other reason.
-    kReasonOther,
-  };
-
-  virtual ~PowerSaveBlocker() = 0;
-
-  // Pass in the type of power save blocking desired. If multiple types of
-  // blocking are desired, instantiate one PowerSaveBlocker for each type.
-  // |reason| and |description| (a more-verbose, human-readable justification of
-  // the blocking) may be provided to the underlying system APIs on some
-  // platforms.
-  static std::unique_ptr<PowerSaveBlocker> CreateWithTaskRunners(
-      PowerSaveBlockerType type,
-      Reason reason,
-      const std::string& description,
-      scoped_refptr<base::SequencedTaskRunner> ui_task_runner,
-      scoped_refptr<base::SingleThreadTaskRunner> file_task_runner);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_BROWSER_POWER_SAVE_BLOCKER_H_